Development and Implementation of the Reflective Cracking Model in the Mechanistic-Empirical Pavement Design Guide

Transcription

1 Development and Implementation of the Reflective Cracking Model in the Mechanistic-Empirical Pavement Design Guide Organizer: TRB Standing Committee on Pavement Rehabilitation August 17, 2016

2 Today s Presenters Moderator Mostafa Elseifi, Louisiana State University Development of the Reflection Cracking Model in the Mechanistic-Empirical Pavement Design Guide Robert L. Lytton, Texas A&M University Reflection Cracking Integration into Pavement ME Design Harold L. Von Quintus, ARA/TRANS Questions & Answers

3 NCHRP is... A state-driven national program The state DOTs, through AASHTO s Standing Committee on Research... Are core sponsors of NCHRP Suggest research topics and select final projects Help select investigators and guide their work through oversight panels

4 NCHRP delivers... Practical, ready-to-use results Applied research aimed at state DOT practitioners Often become AASHTO standards, specifications, guides, manuals Can be directly applied across the spectrum of highway concerns: planning, design, construction, operation, maintenance, safety

5 A range of approaches and products Traditional NCHRP reports Syntheses of highway practice IDEA Program Domestic Scan Program Quick-Response Research for AASHTO Other products to foster implementation: Research Results Digests Legal Research Digests Web-Only Documents and CD-ROMs

6 NCHRP Webinar Series Part of TRB s larger webinar program Opportunity to interact with investigators and apply research findings.

7 Today s First Presenter Development of the Reflection Cracking Model in the Mechanistic-Empirical Pavement Design Guide Robert L. Lytton, Texas A&M University

8 Development of the Reflection Cracking Model in the Mechanistic- Empirical Pavement Design Guide Robert L. Lytton Webinar August 17, 2016 National Cooperative Highway Research Program 1

9 MEPDG Model Reflection Cracking Model Traffic Material Properties INPUT Interlayer Climate EICM Pavement Structure Existing Pavement Conditions Pavement Response (σ, ε) Model: Multi-layer elastic system MODELS Pavement Response Model Stress Intensity Factor (SIF) Artificial Neural Network (ANN) Pavement Distress Models Pavement Distress Model Reflection Cracking (Thermal, Shearing, Bending) Pavement Performance Predictions OUTPUT Pavement Performance Prediction: Reflection Cracking Extent and Severity 2

10 Flow Chart in Overall Selected Test Sections 10 models Field Data Analysis Distress Traffic Axle load distribution Field Data Collection Distress Traffic Pavement Weather Temperature Model Weather data Modeling temperature with depth New temperature model Calibration Process Asphalt modulus Falling weight deflectometer Artificial neural network Calculated number of days Thermal (2) Shear (2) Bending (1) Calibration to field distress Five calibration coefficients Three levels of damage Crack Propagation Model Temperature Traffic shear Traffic bending Artificial neural network models Modulus Stress intensity factors Viscoelastic thermal stress Crack growth 3

11 Mechanisms of Reflection Cracking Bituminous surfacing Thermal crack growth Traffic crack growth Lean concrete roadbase Thermal expansion and contraction Traffic movement Sub-base N fs2 N ft1 Overlay Position I N fb1 N fs1 N ft1 C Bending Stress Shearing Stress Thermal Stress 4

12 Tip of Crack Overlay Old Concrete Layer Stresses at Tip of Crack Bending Stress Shearing Stress Base Course 5

13 Field Data Collection LTPP Test Sections WF DF WNF DNF 6

14 Field Data Collection - Test Sections Category (Overlay/ Exist. Layer) Total Test Sections No. of Test Sections WF DF WNF DNF AC/AC AC/Mill/AC AC/CRC AC/JRC(JPC) AC/SC(FC) AC/Reinforcing/AC AC/Reinforcing/JPC Total

15 Data Collected from LTPP Sections Section (WF zone in New Jersey) AC/AC overlay rehabilitation: July 27 th, 1992 Transverse crack length before overlay: 88.2m Reflective Crack Length (m) /27/92 12/9/93 4/23/95 9/4/96 1/17/98 6/1/99 10/13/00 Observation Date 2/25/02 7/10/03 11/21/04 Crack Length (ratio) No. of Days after Overlay Observed crack length Ratio of reflection crack length to max. length 8

16 Development of Reflection Cracking The amount and severity of reflection cracking follows a sigmoidal curve (S-shape) AREA (%) Traffic or Time High+Medium+Low Severity High+Medium Severity High Severity 9

17 Reflection Cracking Model Factors in reflection cracking model RFAS = DTotal 100 e Scale factor ρ : how wide the rising portion of curve is Shape factor β : how steep the rising portion of curve is ρ β Crack Length β < 1.0 β = 1.0 β > 1.0 Crack Length e -1 = 36.8% Traffic or Time t =ρ 1 t =ρ 2 t =ρ 3 Traffic or Time 10

18 Calibrated Models for LTPP Sections LTPP section (WF zone in New Jersey) AC/AC overlay Reflective Crack Length (ratio) measured predicted H+M+L H+M H No. of Days after Overlays Calibrated Parameters Values Severity Parameter β ρ H+M+L H+M H N/A N/A 11

19 Mechanisms of Reflection Cracking Bituminous surfacing Thermal crack growth Traffic crack growth Lean concrete roadbase Thermal expansion and contraction Traffic movement Sub-base N fs2 N ft1 Overlay Position I N fb1 N fs1 N ft1 C Bending Stress Shearing Stress Thermal Stress 12

20 Rectangular Tire Patch Length Uniform Pressure Width Tire Length Tire Length = Tire Load Tire Pressure Tire Width 13

21 Eight Categories on Axle Type and Number of Tires Vehicle Class Single Axle Tandem Axle Tridem Axle Quad. Axle No. 1 No. 2 Single Tires No. 3 No. 5 No. 7 Dual Tires No. 4 No. 6 No. 8 14

22 Example: Category 1 of LTPP Section in 2004 Cumulative Axle Load Distribution P Tire Length (in.) Measured Model P 1 L 2 L 1 15

23 Pavement Temperature Model Model developed by Dr. Charles Glover s research group, Department of Chemical Engineering, Texas A&M. Outgoing longwave Solar radiation radiation Atmospheric downwelling Heat convection longwave radiaiton by wind α : Albedo T a : Air temperature q s : Solar radiation ε : emissivity coefficient ε a : absorption coefficient Pavement Heat conduction к: Thermal conductivity (Model source: Xin Jin, Rongbin Han, and Dr. Charles Glover, Department of Chemical Engineering, Texas A&M University) 16

24 Albedo Distribution in Winter

25 Temperature Flutuation Pattern Around Daily Average Temperature (Degree C) Hours Texas ( ) Texas ( ) Texas (48-A800) South Dakota ( ) Utah ( ) Nevada ( ) 18

26 Pavement Structural Cases 19

27 Modeling of Stress Intensity Factor (SIF) by Artificial Neural Network (ANN) (1/2) AC_AC AC_PCC 20

28 Modeling of Stress Intensity Factor (SIF) by Artificial Neural Network (ANN) (2/2) Pure_Bending_AC_AC_Single_Tire_Together Pure_Bending_AC_AC_Single_Tire_Together (Only Positive) 21

29 Modeling of Relaxation Modulus by Artificial Neural Network (ANN) (2006 Model) Witczak 2006 Model 3/4 (%) Input R Output 2 Gradation Volumetric Binder Data Witczak ANN 3/8 #4 #200 V a V beff Log G* δ c E* psi (%) (%) (%) (%) (%) 10 6 psi deg 60 Predicted IE*I (GPa) Observed IE*I (GPa) Witczak 2006 ANN

30 Crack Growth Model - Paris Law dc dn n 0 0 ( ) 1 mix g log A= g + log D + g logσ t n ak = w() t dt n = A K a = g + g m k mmix t E(t,T) D 1 = creep compliance coefficient σ t = tensile strength m mix = slope of complex moduli versus loading times g 0 ~ g 6 = coefficients varying with climate zones a k = the viscoelastic stress pulse effect m mix Loading Time 23

31 Crack Growth Model - Paris Law EtT (, ) 1000 r = in / mm, T = 77 F, σ t = > Temperature EtT (, ) 1000 r = 0.5 in / mm, T = 77 F, σ t = > Traffic Coefficient Climatic Zone Wet-Freeze Wet-No Freeze Dry-Freeze Dry-No Freeze g g g g g g g

32 Load Wave Shape for Tandem Axle 4.0 ft Overlay L j L j Old Surface 2.0 ft 2.0 ft Crack or Joint 5.0 ft L j L j 5.0 ft W ( t ) Load Wave Shape (1 4 + L j ) ft. [ W ( t )] n (0.92) n (0.92) n (0.72) (0.82) n (0.82) (0.72) n (0.095) t 25

33 Calculated Number of Days Position II N fs2 N ft2 Overlay Position I N fb1 N fs1 N ft1 C Bending Stress Shear Stress Thermal Stress N fb1 = Number of days for crack growth due to bending to reach Position I. N ft1 = Number of days for thermal crack growth to reach Position I. N fs1 = Number of days for crack growth due to shearing stress to reach Position I. N ft2 = Number of days for thermal crack growth to go from Position I to Position II. N fs2 = Number of days for crack growth due to shearing stress to go from Position I to Position II. 26

34 Calibration Quantities 100% Percent of Reflected 36.8% High + Medium+ Low Medium+ High High severity 0 ρ LMH ρ MH ρ H Number of Days Damage 27

35 Calibration Model Set N fb1 N fb1 N ft 2 ρlmh = N fb1 α0 + α1 + α2 + N ft 2 α3 + α 4 N ft1 N fs1 N fs 2 Calibration Coefficients : α, α, α, α, α, β LMH N fb1 N fb1 N ft 2 ρmh = N fb1 α5 + α6 + α7 + N ft 2 α8 + α 9 N ft1 N fs1 N fs 2 Calibration Coefficients : α, α, α, α, α, β MH N fb1 N fb1 N ft 2 ρh = N fb1 α10 + α11 + α12 + N ft 2 α13 + α 14 N ft1 N fs1 N fs 2 Calibration Coefficients : α, α, α, α, α, β H 28

36 SENSITIVITY ANALYSIS HOW DOES THE TIME-SCALE PARAMETER, ρ, VARY WITH OVERLAY THICKNESS? 29

37 Sensitivity analysis of ρ LMH for AC over AC pavement structure in a Dry-No Freeze climate zone Scale coefficient (ρ LMH ), log Thickness, inch

38 Sensitivity analysis of ρ H for AC over AC pavement structure in a Dry-No Freeze climate zone Scale coefficient (ρ H ), log Thickness, inch

39 Sensitivity analysis of ρ MH for AC over JPC pavement structure in a Wet-Freeze climate zone Scale coefficient (ρ MH ), log Thickness, inch

40 Sensitivity analysis of ρ LMH for AC over Reinforcing over PCC pavement structure in a Wet-Freeze climate zone Scale coefficient (ρ LMH ), log Thickness, inch

41 Reflection Cracking Integration into Pavement ME Design Harold L. Von Quintus Webinar August 17, 2016 American Association of State and Highway Transportation Officials 34

42 Outline for Session 2: 1. Overview of Enhancement to MEPDG 2. Inputs Specific to Reflection Cracking 3. Calibration of Reflection Cracking Transfer Function 4. Application/Demonstration of Reflection Cracking Models for Rehabilitation Design Enhancement to AASHTOWare Pavement ME Design in FY2015: Version 2.2 &

43 AASHTO Pavement ME Design Task Force Members: 1. Judith Corley-Lay, P.E.; NCDOT, Chairperson 2. Vicki Schofield, AASHTO Project Manager 3. John Donahue, P.E.; Missouri DOT 4. William Barstis, P.E.; Mississippi DOT 5. Jay Goldbaum, P.E.; Colorado DOT 6. Marta Juhasz, P.E.; Alberta Transportation 7. Mehdi Parvini, P.E.; California DOT 8. Felix Doucet; TAC Liaison 9. Tom Yu, P.E.; FHWA Liaison 10. Shane Marshall, P.E.; Utah DOT, SCOJD Liaison 11. Jack Dartman, Montana DOT; T&AA Liaison 36

44 Reflection Cracking Integration into Pavement ME Design Based on results and methodology developed from NCHRP Project 1-41 A special thank you to: Bob Lytton and Sheng Hu (Texas Transportation Institute): explanation on the models/equations. Halil Ceylan (Iowa State University): completed neural networks. 37

45 Enhancement to MEPDG Earlier Version; pre 2.2 Regression equation Fatigue cracks Version 2.2 & Higher Fracture mechanics Fatigue cracks Transverse cracks 100 RC = 1 a + + e ( c) bt( d ) RCR i = C c c5 e ( ( )) Log DI i 38

46 Enhancement to MEPDG Earlier Version; pre AC over AC 2. AC over PCC Version 2.2 & Higher 1. AC over AC 2. AC over AC with seal coat and interlayer 3. AC over intact JPCP 4. AC over fractured JPCP 5. AC over CRCP 6. Semi-Rigid Pavement 7. AC over Semi-Rigid RC a = 1 + e ( c) bt( d ) RCR i = C c c5 e ( ( )) Log DI i 39

47 Enhancement to MEPDG Expanded Pavement Design Types: 1. Overlay with seal coat and interlayer 2. Semi-rigid pavement 3. Overlay of semi-rigid pavement 4. Overlay of PCC; intact and fractured 40

48 Outline for Session 2: 1. Overview of Enhancement to MEPDG 2. Inputs Specific to Reflection Cracking 3. Calibration of Reflection Cracking Transfer Function 4. Application/Demonstration of Reflection Cracking Models for Rehabilitation Design 41

49 Inputs to Software Performance criteria and reliability Condition of existing pavement Load transfer efficiency of cracks and/or joints Mixture properties 42

50 Performance Criteria and Reliability AC of AC Pavements AC of AC AC seal coat and interlayer of AC 43

51 Performance Criteria and Reliability AC of PCC Pavements AC of intact JPCP AC of fractured JPCP AC of CRCP 44

52 Condition of Existing Pavement AC over AC AC over Semi-Rigid 45

53 Condition of Existing Pavement AC over Fractured JPCP 46

54 Condition of Existing Pavement Semi-Rigid Pavement 47

55 Load Transfer Efficiency Flexible and PCC pavements Measured in accordance with LTPP procedure Tied to crack severity for calibration Severity LTE, percent Low 85 Medium 50 High 30 48

56 Overlay Mixture Properties No new or additional mixture properties needed 49

57 Outline for Session 2: 1. Overview of Enhancement to MEPDG 2. Inputs Specific to Reflection Cracking 3. Calibration of Reflection Cracking Transfer Function 4. Application/Demonstration of Reflection Cracking Models for Rehabilitation Design 50

58 Sampling Matrix Existing Pavement Condition Overlay Thickness AC over AC Pavements Interlayer/Climate AC None Seal Coat DF DNF WF WNF DF DNF WF WNF DF DNF WF WNF Good Mod. Poor Thick Thin Thick Thin Thick Thin Data Sources: LTPP and other agency test sections. Total Number of Test Sections: 58 51

59 Sampling Matrix AC over PCC Pavements Pavement Type Existing Condition Overlay Thickness Climate DF DNF WF WNF Fractured Intact Not Applicable Good/Moderate Poor Thick Thin 3 1 Thick Thin Thick Thin Data Sources: LTPP, New York City composite test sections, other agency test sections; 60 test sections. 52

60 Sampling Matrix Semi-Rigid Pavements Pavement Type Existing Condition Overlay Thickness Climate DF DNF WF WNF New AC over CTB Not Applicable Thick Thin Data Sources: LTPP other agency test sections; Total number of sections: 55 53

61 Calibration Coefficients Calibration Coefficients Transverse Cracks Pavement Type AC over AC AC over Intact JPCP AC over CRCP or Fractured JPCP Semi- Rigid K K K C C C C C Critical coefficients, local calibration: C1, C2 and C5. AC over Semi-Rigid 54

62 Calibration Coefficients Calibration Coefficients Fatigue Cracks Pavement Type AC over AC AC over Intact JPCP AC over CRCP or Fractured JPCP Semi- Rigid K NA NA K NA NA K NA NA C NA NA C NA NA C NA NA C NA NA C NA NA Critical coefficients, local calibration: C1, C2 and C5. AC over Semi-Rigid 55

63 Calibration Coefficients AC over Flexible Pavements: Fatigue Cracks Transverse Cracks 56

64 Outline for Session 2: 1. Overview of Enhancement to MEPDG 2. Inputs Specific to Reflection Cracking 3. Calibration of Reflection Cracking Transfer Function 4. Application/Demonstration of Reflection Cracking Models for Rehabilitation Design 57

65 Application of Models Sensitivity of load transfer efficiency or crack severity: Load transfer efficiency is important. 58

66 Application of Models Eastern Colorado Existing AC Thickness: 6 in. Distress Severity: Medium 90% Reliability Effect of AC overlay thickness. 59

67 Application of Models Fractured JPCP Southern Arizona Slab thickness 10 inches AC overlay 5 inches Effect of reliability for transverse cracking. 60

68 Application of Models Fractured JPCP 90% Reliability Slab thickness 9 inches AC overlay 5 inches Effect of LTE for fractured JPCP. 61

69 Application of Models Fatigue cracking predictions for AC over AC. 62

70 Application of Models Transverse cracking predictions for AC over AC. 63

71 Application of Models Transverse cracking predictions for AC over fractured PCC. Block cracking recorded in LTPP. 64

72 Reflection Cracking addendum is available through the ME-Design Resource Website for downloading the software: Addendum #FY2015.4; dated August

73 QUESTION AND ANSWER SESSION Comments & suggestions for future webinars are welcomed. 66